This was partly in response to something said in this thread:http://www.axiomaudio.com/boards/ubbthreads.php?ubb=showflat&Number=298000#Post298000
Ok I had the day off and did an unscientific inverted speakers test. Not sure if I hit on what Alan was suggesting but I put the right M80 on top of tote boxes so that itís tweeters were just about level with the tweeter of the left M80 sitting on the ground. Hooked them up with a switch so I could feed them both a signal at the same time or separately. I also repeated the test with the right M80 sitting upside down on top of the center M80.
With both playing the same mono signal I quickly noticed the mid-bass of the right M80 (inverted and elevated) was weaker. I noticed the same thing when A/B comparing the two M80 sitting on top of each other (inverted/elevated one had weaker mid-bass). Sitting with my ears vertically aligned as close as I could with both speakers tweeters I couldnít hear any tonal differences except for the drop in mid-bass of the elevated/inverted speaker.
I also noticed that the soundstage of the elevated speaker in both cases sounded more natural. By that I mean more depth, vertical expansion and ambience. As a test I elevated the left speaker on a tote box (about 1.5í high) leaving it right-side-up while leaving the right speaker upside down on itís 3 totes. Now both speakers sound identical. Only by A/B comparing them with the switch could I tell that the right speaker sounded slightly more elevated. I also played them in stereo like this and the soundstage sounded normal.
Iíve always like the sound of my speakers elevated to I switch them both to right-side-up on a single tote box and they sounded much better in my seat than when sitting on the ground (note: my seating is high putting my ears on level with the top the M80s when they are on the floor). However, I now noticed a problem. When moving my ears vertically I noticed the tone of the speakers changed as my ears passed the level of each set of drivers with the frequencies produced by those drivers becoming dominant. The farther I was from the speaker the less pronounced but it was very noticeable.
Having never noticed this before (my ears have never passed the plane of each driver pair before) I was curious what was happening. I got the idea to push the reclining backs of the chaise lounges down and surprise the ďbeamingĒ effect from each driver pair disappeared. There is still a slight tonal difference (more natural sounding voices) with my ears on level with the mid-range drivers rather than the tweeters but it is now very subtle. And the soundstage opened up like I havenít heard since moving my bed out of the living room for ďrealĒ furniture. Iíve known since buying the ďacoustic black holeĒ futon in my apartment that furniture has a big effect on room acoustics but this experience was striking.
This, however, left the center M80 sounding meek still sitting there on the ground. Since I cant elevate it more than a few inches because of the screen I tried tilting it back so that the mid-range drivers rather than the tweeters were pointed at ear level. It now seems to blend seamlessly with the elevated mains. I tested it with a few movie scenes and didnít notice any vertical or tonal shifts while sounds were panning. It also gave me a better tonal balance in the vocal range than Iíve ever heard before.
In summary I found that elevating the M80s 1.5í off the ground while right-side-up or upside down 4í off the ground had the same effect on the soundstage, as long as the tweeter/mid-range drivers were roughly on the same vertical plane (within a couple feet of each other). Elevating the M80 off the ground (more than 1í in this case) noticeably reduced the mid-bass. Elevating the tweeters and mid-range drivers above the rooms seating backs improved the soundstage for 2ch music by increasing itís depth, vertical expansion and ambience. This also greatly improved the mainís integration with the surrounds creating a more seamless surround soundstage. Tilting the M80 back to aim the mid-range drivers at the ears slightly improved voices and simulated elevating the speaker at least in the mid-range frequencies and up.